Device for indicating the position of the platform of cranes with articulated booms,especially camera cranes



United States Patent [56] References Cited UNITED STATES PATENTS [72] Inventor Adrian Birbanescu Bucharest, Romania 3 6 Mwm89m8 I/ 44/0B5 B 5 22% 9 55 33 M Q m V.V. d wwmmww RR JKRL 785136 345666 999999 HHHHHH 382899 873074 9688500 375533 742907 222233 A Q. m m mm MR t m a P w B m s 9WDfl$ 1 n9 9 l a so e um w unw4a 9 m m -].3 5 CPJR Q 08 mmfl m una fl AFPA P 111]] .l] 253 23 2247 33 .l...l[.l [l

[3 l 1 Nos. 49524 and 49525 Primary ExaminerLouis J. Capozi AttorneyArthur O. Klein r N wmmwmm t o .mmammwm n l mhm ml m m own um w md tfi hfl T n IV m mm mnme m a a .m edv ma mam .m m t m n m ww r e n w .mm w ml m m md w e mu t u o wlm0 om .l dmn wv. nd e 0 n Mw.l mab C m mfmwm n d mflnm mmmw mm.w w. .m mm h i. mm m OiD. Armhwbpu A r m o M N A m C n n w P l EWC m TE GME I I S CM 8 F0 H 100 g D B mkm mm" m A nL A ELUES mrm m mummm DTAC7 M 5 shaft axially extending from the pivotal connection between the base and the lower boom. Two

pairs of levers mounted on a h c e mm a n lm 0 :0. lw e VTW h e fm 00m r-O p-lO b 6 Wm a e C e .m n i n ole m m D. m w ee hh.w It! .20 4 UN 81 MM 0 G m MS m d and mm m ll.

e lever is parallel to either nisms are operapair of levers and are I24, 135: /86: 352/34, 243: sultant horizontal and l 82/141, 2; 248/] l, 124, 125, 183; 280/9l vertical motions of the upper and lower booms.

adapted to respectively record the re DEVICE FOR INDICATING THE POSITION OF THE PLATFORM OF CRANES WITH ARTICULATED BOOMS, ESPECIALLY CAMERA CRANES The present invention relates to a mechanical device that indicates continually the position of the platform of cranes with articulated booms, more especially of camera cranes by means of a coordinate indicating system. The position of the crane platform is indicated in terms of the separate movements, in the same plane, of the individual booms. In this way the trajectory traversed, by the crane platform is illustrated on a rotating cylinder.

Another and particularly important object of the present invention is to provide a hydraulic servomechanisrn which serves to produce rectilinear movements of the crane platform.

Devices are known which cooperate "only with a single boom and indicate only the height of the camera platform and the angle of rotation of the boom relative to its vertical axis. Also there are known devices for lifting cargo that indicate, in terms of the boom inclination i.e. of the cargo lever, the maximum load that can be lifted by the crane.

Devices like those mentioned above may not, however, be used with cranes having articulated booms for indicating the coordinates of the position of the platform, because said coordinates do not result from a simple movement, but from the composition of the movements of both booms.

Electric devices are also known that compute the spatial coordinates of a point situated at the end of two links pivotally connected to each other and movable in space, said computation being performed by vectorially adding the link move ments in terms of the link lengths and of the link inclinations relative to a given coordinate system. Such devices are, how ever, used for controlling some machine tools according to a given program and they are complicatedand necessitate a separate power source.

The device according to the invention eliminates these disadvantages by decomposing the movements of the two booms, in the vertical plane containing them, by means of slide mechanisms into vertical and horizontal linear components; the vertical components being added separately, and the horizontal components also being added separately, said mechanisms being designed so that these sums represent at a certain scale the crane platform coordinates relative to a given y coordinate system, more particularly the platform ordinate and abscissa.

In order to make possible crane movements only in one plane, i.e. to maintain in the platform'ordinate or abscissa constant during the movement, the camera crane of this invention is provided with booms that are driven by well-known hydraulic cylinders. These cylinders are controlled by a hydraulic servomechanism in such a way that the indicator of the coordinate which is perpendicular to the plane containing the movement remains fixed relative to the component on which the respective coordinate is measured in the indicating device.

In order to indicate the height of the camera platform, the movement of the upper boom is transmitted by means of a parallelogram mechanism, consisting of three levers, to a slide provided with an indicator, while the'movement of the lower boom is transmitted by means of a shaft mounted in the lower articulation of said boom to a lever and a pin engaging the groove of a cylinder, so that said lever moves the cylinder along a vertical axis in such a way that thedistance between the final position of the indicator anda zero mark on the cylinder is proportional to the change in height of the crane platform.

For the indication of the abscissa of the crane platform, the

movement of the upper boom is transmitted by means of the same parallelogram mechanism consisting of three links and a shaft, to a lever which by means of a slide mechanism drives an indicator, while the movement of the lower boom is transby means of a shaft fixed in the lower articulation of the lower boom, to a lever which by means of a slide mechanism drives a rule in such a way that the distance between the final position of the indicator and a ze'romark on the rule is proportional to the change in the abscissa of the crane platform.

For the indication of the angular position of the vertical plane containing the crane booms, relative to an initial vertical plane, the crane rotation is transmitted by means of a belt from a pulley situated in the verticalaxis of the crane and fixed relative to the initial vertical plane,'to a second pulley coaxial with the cylinder of the height indicating mechanism, said second pulley being able to turn said cylinder, so that the angle of rotation of the cylinder corresponds to the angle of rotation of the crane.

In order to make the invention more clearly understood, reference will be made to the accompanying drawing which is given by way of example and in which:

FIG. 1 is an isometric schematic view of the device of this invention;

FIG. 2 is a vector diagram which indicatesthe mathematical principle of the device;

FIG. 3 is an isometric schematic view of the hydraulic servomechanism designed only for producing vertical movev ments of the crane platform; and

FIG. 4 is a block diagram of the servornechanism illustrated in FIG. 3.

For the indication of the height of the crane platform, the device according to the invention is provided with a parallelogram mechanism consisting of three links 1, 2 3, link 1 being fixed to the upper boom of a crane in such away that link 3 is parallel to said upper boom as illustrated in F I65. I and 3. At its freeend the link 3 drives by means of a slide mechanism a component 4 which is slidably mounted in a support member 4a and which is provided with an indicator 5. The support member 4a is firmly connected to the crane pedestal member 27. The component 4 is mounted in such a way that the vertical movements of the indicator 5 correspond to the vertical movements of the crane platform (not illustrated), which is operatively connected to the upper end la of the upper boom caused by the upper boom movements. ln'the lower articulation of the lower boom there is coaxially mounted a shaft 6 fixed to the lower boom. On the shaft 6 there is fixedly secured a lever 7 parallel to the lower boom and provided with a pin 8 that engages a disc having a groove 9, said disc being coaxially secured on the cylinder 10. The cylinder lil'is slidably moving up and down a vertical shaft 11, being driven by the pin 8. The vertical movements of the cylinder 10 correspond to the vertical movements of the crane platform caused by the movements of the lower boom. The shaft '11 is slidably and rotatably supported in a bearing support 1 1a. The bearing support 11a is mounted on a plate 116 extending from the crane pedestal.

'Duringthe operation of the device, if the lower boom has turned up with an angle a relative to the horizontal, and if the radius of the lever 7 is equal to r,, the cylinder 10 reaches the height Z =r,sina. Similarly, if the upper boom has turned up with an angle )3 relative to the horizontal, and if the radius of the lever 3 is equal to r,, the indicator 5 reaches the height Z =r sinB. Between the indicator 5 and a zero mark taken as origin on the cylinder 10 appears a distance If the length of the lower boom is 1,, and if the length of the upper boom is 1 the angles a and [3 being the same as above, from FIG. 2 follows that the height of the crane platform is If between the lengths of the crane booms and those of the levers 3 and 7 exists the proportionality than the distance AZ defined as above and'the reading on the cylinder 10 represents at a scale It the height Z of the crane platform.

For the indication of the abscissa of the position of the crane platform use is made of the same parallelogram mechanism consisting of the links 1, 2, 3, the link 3 being fixed on one end of a hollow shaft 12 which rotates freely on the shaft 6, On the other end of the shaft 12 there is fixed a lever 13, parallel to the upper boom, said lever driving at its free end, by means of a slide mechanism, a rod 14 provided with an indicator a. The rod 14 is slidably supported in a support member 140, which is connected to the crane pedestal member 27. The horizontal movements of the indicator a correspond to the horizontal movements of the crane platform caused by the movements of the upper boom. On the shaft 6 there is fixed a lever. 15, parallel to the lower boom and driving by means of a slide mechanism aruler 16 which is slidably supported on a support member 16a, which is connected to the crane pedestal member 27. The horizontal movements of the ruler l6 correspond to the horizontal movements of the crane platform caused by the movements of the lower boom.

During the operation, if theangle a is the same as before mentioned and if the radius of the lever 15 is equal to r the abscissa change of the end of. the lever 15 is X,=r costa. Similarly, if the angle B is the same as above and if the radius of the lever 13 is equal to r.,, the indicator a changes the abscissa X -r ,a and a zero mark taken as origin on the rule 16 appears a distance With the same notations as in FIG. 2 the net change in the abscissa of the crane platform is X=1 cos 3-1 cos a.

If between the lengths of the camera booms and those .of the levers 13 and 15 exists the proportionality then the distance AX defined as above and read on the rule 16 represents at scale Hit the change in height X of the crane platform.

In order to indicate the rotation of the vertical plane containing the crane booms, relative to an initial vertical plane, there is. axially in the crane pedestal, and fixed relative to the initial vertical plane, a pulley 17 connected by means of a belt 18 to another pulley 19 which is coaxially mounted on the shaft 11. By means of a.sliding key (not illustrated) which is engaged in a key groove b of the shaft 11, the pulley 19 rotates the cylinder 10, said cylinder being able to move at the same time up and down in the bearing support Ila. If the pulleys 17 and 19 are of the same diameter, then the angle of rotation of the-cylinder 10 read against the height indicatorS is equal to the angle of rotation of the crane relative to the given initial P nc- An alternate embodiment of the invention is illustrated in F lG..3 for effecting a movement of the crane platform only in the. vertical plane. The upper boom of the crane is driven ,by a hydraulic cylinder 20 controlled by means of a hydraulic valve 21- and a spool 22. The valve is moved by the rod 14, and the spool-by the ruler 16. With this arrangement, if the cylinder 28 for, actuating the lower boom is controlled directly, the cylinder 20- for actuating the upper boom follows the movemferitof the lower boom in such a way that the position of the r0614 remains unchanged relative to the ruler 16.

[Assuming that the hydraulic cylinder for the lower boom is cont-rolled in such a way that the lower boom moves upwards from the horizontal, the crane platform moves rightwards. The ruler; l6 translates mechanically this movement into a leftward movement of the spool 22. Then, by means of a conduit 23, thelower chamber of the cylinder. 20 is connected with a pressure. conduit 24, while the upper chamber is connected through a conduit 25. toa return conduit 26. It follows that the upper boom will be, lifted, moving thus leftwards the crane platform. The rod 14 ,will'translate mechanically this movement into a leftward movement of the valve 21, until the com-v munications with the conduits 23 and 25 are again closed, Thus the servomechanism controls the upper boom move ments in such a way that any movement of the rod 14, with its indicator a, relative to the ruler 16 is canceled, i.e. any deviation of the crane platform movement from a strictly vertical movement, deviation caused by the movement of the lower boom, is canceled by the movement of the upper boom end the crane platform travels only vertically. This movement is read against the indicator 5, on the cylinder 10. I

One suitable arrangement of the input, output and feedback signals of the above system is identified in FIG. 4. As it may be seen the movements .of the lower boom are controlled directly, i.e. by an open loop, and are translated by means of the ruler 16 into an input signal for the valve 21 and the spool 22 controlling the hydraulic cylinder 20. The movements imparted by this hydraulic cylinder to the upper boom are translated by the indicator a into a feedback signal for the valve 21 and its spool 22.

In order to obtain movements of the crane platfonn only in a horizontal plane, use is made of a similar servomechanism (not illustrated) the valve 21 being however put into movement by the indicator 5, and the spool 22 by the cylinder 10.

A servomechanism like that described above may control movements of the crane platform also in other planes, if the indicator device is so designed that it decomposes the movements of the two booms according to a suitably chosen coordinate system.

In order to obtain the same results, i.e. movements of the crane platform only in one plane, use may be made also of ser vomechanisms in which the indicator device drives the hydraulic valve and its spool by means of differential levers.

Also, the characteristics of the system may be improved if besides the projections of the two boom movements as input and feedback signals there is also made use of the derivatives relative to the time of the above-mentioned projections, i.e. the projections of the velocities and of the accelerations of the two boom movements. The velocities may be obtained for example by means of centrifugal tachometers or of tachometric I generators driven. by the indicators described above, through multiplying gears. Similarly, the accelerations may be obtained by means of accelerometers. The output signals of the, velocity and acceleration transducers may be used asinputs for separate hydraulic valves whose outflow is superimposed on that of the valve controlled by the indicator device. Alternately, the outputs of the various transducers may be superimposed electrically and used as inputs for an electromagnetic valve.

The device according to the invention presents the following advantages:

it indicates both the movements of each separate boom and the resultant of their movements;

it makes possible to follow the movements of the booms in comparison with the crane rotation; It makes possible to traverse in a certain part of the space any given trajectory, more especially with camera cranes;

it is capable of indicating the load deflections in order to establish the maximum permissible load with craneshaving articulated booms;

it makes possible the immediate determination of the height of a platform lifted by a crane having an articulated boom; and

it makes possible rectilinear movements of the platform of cranes having articulated booms, more especially camera cranes.

Although my invention has been illustrated and described with reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments but is capable of numerous modifications within the scope of the appended claims.

Iclaim:

1. In a device for indicating information relating to theposi tion of the top end of an articulated boom mechanism having a base which isrotatably mounted about a vertical axis, comprising in combination: i

a lower boom member being pivotally Connected at one of its ends to said base; an upper boom member pivotally connected to said lower boom member of the other end thereof; a shaft axially extending from the pivotal connection between said lower boom member and said base; a sleeve coaxially and rotatably mounted over said shafi; a first pair of levers fixedly secured to said sleeve so as to rotate jointly therewith, said first pair of levers being parallel to said upper boom member during their respective movement; 1

a second pair of levers fixedly secured to said shaft so as to rotate jointly therewith, said second pair of levers being parallel to said lower boom member;

an indicating cylinder rotatably mounted about a vertical axis and being reciprocally movably mounted along said vertical axis, said cylinder havingannular groove means;

one lever of said second pair of levers having a projecting pin which extends into said annular groove means so that when said one lever rotates it moves said indicating cylinder along its vertical axis a distance'which is proportional to the vertical distance traversed by said lower boom member when it pivots about said base;

first slide means operatively connected to said other lever of said second pair of levers; said other lever moving said first slide means horizontally a distance which is proportional to the horizontal distance traversed by said lower boom member when it pivots about said base;

of said upper boom member and the length of the other lever in said first and second pairs of levers is proportional to said lower boom member.

3. In the device for indicating infon'nation as set forth in claim 2 and wherein said second slide means includes first indicating means adapted to cooperate with said first slide means so as to indicate the resultant combined horizontal movement of said upper and lower boom members.

4. In the device for indicating information as set forth in claim 2 and wherein said third slide means includes second indicating means adapted to cooperate with said indicating cylinder so as to indicate thereon the resultant combined vertical movement of said upper and lower boom members.

5. In the device for indicating information as set forth in claim 2 and wherein a pulley operatively connects said indicating cylinder to said base in a manner which causes said cylinder and base to rotate equiangularly.

second slide means operatively connected to one of said levers of said first pair of levers, said one lever moving said second slide means horizontally adistance which is proportional to the horizontal distance traversed by said upper boom member when it pivots about said lower boom member; and

third slide means operatively connected to said other lever 6. In the device for indicating information as set forth in claim 5 and wherein:

first hydraulic actuating cylinder means are pivot'ally connected to said upper boom member at one of their ends and to said lower boom member at the other end;

hydraulic fluid cylinder distributing means fixedly secured to said second slide means so as to move horizontally jointly therewith;

a fluid distributing piston slidably disposed in said hydraulic fluid cylinder means, said piston being fixedly secured to said first sl ide means so as to move 'ointly therewith; first hydraulic inlet and outlet con un means operatively connecting said hydraulic fluid cylinder to said first hydraulic actuating cylinder; and second hydraulic inlet and outlet conduit means operatively connecting said hydraulic fluid cylinder distributing means to a source of hydraulic power; said hydraulic fluid cylinder distributing means and said piston slidably disposed therein being constructed and arranged so that said first hydraulic cylinder means is only hydraulically energized via said hydraulic fluid cylinder distributing means when the horizontal movements of said upper and lower boom members are not equal in sign and opposite in direction. 7. In the device for indicating information as set forth in claim 6 and wherein second hydraulic actuating cylinder means are pivotally connected to said lower boom member for pivotally moving it with respect to said base. 

